Interleukin 12 is a heterodimer consisting of a protein with a molecular weight of about 40 kD (hereinafter sometimes abbreviated "P40" or "P40 subunit") and a protein with a molecular weight of about 35 kD (hereinafter sometimes abbreviated "P35" or "P35 subunit"), and is a cytokine with such bioactivity as to activate natural killer cells and type 1 helper T cells, being abbreviated as IL12. Concerning IL12, some literature has been published. In addition to human IL12, the cDNAs of mouse IL12 (Shoenhaut et al: J. Immunol. 148, 3433-3440 (1992) and bovine IL12 (GenBank Database Registration Nos. U1 1815 and U14416) were cloned by gene manipulation techniques, and their application as remedies against cancers, viral diseases, etc. are being researched and developed.
For IL12, treatment effects in mouse model experiments against tumors, infectious diseases, allergies, and the like especially by its activity in boosting the cell-mediated immune response have been reported in the literature such as Nastala et al: J. Immunol. 153, 1697-1706 (1994), Gazzinelli et al: Proc. Natl. Acad. Sci. USA 90, 6115-6119 (1993) and Chirgwin et al: Biochemistry 18, 5294 (1979), and clinical trials of IL12 as a remedy against human cancer and human infectious disease has already started. However, it is not yet reported that canine IL12 has been cloned.
Dogs are known to suffer from various cancers such as mammary gland tumor, various viral diseases such as Parvovirus infectious disease and distemper infectious disease, allergic dermatitis and the like. Therefore, if canine IL12 were to become easily available, it is expected that its application as a canine antitumor drug, antiallergic drug and antiviral drug would be attempted.
Presently, few remedies and preventive agents effective against these canine diseases are available. For example, most dogs suffering from cancer come to hospitals after their tumors have grown, and even if the tumors are ablated by surgery, they soon die after the operation because of metastasis. Also, for skin diseases often seen with dogs, they cannot be cured in most cases even if steroids are administered repetitively for long periods of time as a treatment. As a consequence, fast and continuously acting remedies are being demanded. It is expected that new applications will be attempted for these canine diseases now left without any effective remedy if canine IL12 becomes available.